I'm team captain of RobotsByTheC, and I filmed that video. That is in fact our robot from last year. I was kind of surprised the robot was able to do it. Its incredibly top heavy with its center of mass far in the front. The material on the bridge actually has about half the friction of lexan, the material used on the actual bridge. We used fiberboad, because lexan is expensive. I'de be happy to take any other questions.